Marketing company Jung von Matt pulled a prank on shipping companies like TNT, UPS, and DPD by forcing their employees to carry around boxes that had massive advertisements on them for their common competitor, DHL. The company pulled this off by using a special technology on the boxes that made them appear black when they were in a cold, dark warehouse. However, after the boxes had a chance to warm up in their trucks, the black changed into yellow and red adverstisements for DHL that read "DHL IS FASTER." DHL told RightThisMinute they had nothing to do with the clever marketing ploy, and that Jung von Matt came up with it as a part of an internal competition going on within their company.